1. Field of the Invention
The present invention relates to the field of optical communication technology, and more particularly to a dual rate receiving device.
2. Background of the Invention
An optical communication apparatus generally works at various working rates, which requires that an optical transceiver module can work at various rates, so that difficulties are brought to the practical circuit design. To be compatible with a high rate application, devices of the optical transceiver module need to satisfy requirements of high rate and wide bandwidth. However, when the devices with the high rate and the wide bandwidth work at a low rate, a sensitivity index is generally unsatisfactory.
The contradiction is particularly prominent in a dual rate receiver of a 10-Gigabit Ethernet passive optical network optical line terminal optical transceiver module. To be compatible with an existing Gigabit Ethernet passive optical network optical network unit apparatus, in the 10-Gigabit Ethernet passive optical network optical line terminal optical transceiver module, 10.3125 Gbps and 1.25 Gbps burst optical signals need to be received. If it is optimally designed that the receiver works at a high-speed rate of 10.3125 Gbps, a receiving sensitivity at 1.25 Gbps is degraded. On the contrary, performances of the high rate receiver cannot be guaranteed.
Furthermore, when the receiver works in a burst working state, a dual rate optical receiving component and a subsequent signal amplifying circuit need to implement conversion of a burst signal within the time smaller than 400 ns. The working mode brings difficulties to apparatus selection. Bandwidth switching circuits of chips of a business class trans-impedance amplifier and a limiting amplifier cannot satisfy the requirement of 400 ns rate switching.